U.S. patent application number 12/775223 was filed with the patent office on 2010-08-26 for method and apparatus for gastrointestinal stimulation via the lymphatic system.
Invention is credited to Allan C. Shuros.
Application Number | 20100217346 12/775223 |
Document ID | / |
Family ID | 38791294 |
Filed Date | 2010-08-26 |
United States Patent
Application |
20100217346 |
Kind Code |
A1 |
Shuros; Allan C. |
August 26, 2010 |
METHOD AND APPARATUS FOR GASTROINTESTINAL STIMULATION VIA THE
LYMPHATIC SYSTEM
Abstract
An implantable gastrointestinal (GI) stimulation system includes
an implantable medical device and at least one stimulus delivery
device configured to be placed in one or more lymphatic vessels of
a patient, such as the patient's thoracic duct and/or vessels
branching from the thoracic duct. In one embodiment, the
implantable medical device includes a GI stimulation circuit to
deliver electrical stimulation pulses to one or more target regions
adjacent to a lymphatic vessel through the stimulus delivery
device. In one embodiment, to control obesity, the electrical
stimulation pulses are delivered to the organs and/or nerves of the
GI tract to create a sensation of satiety and/or to expedite food
movement through the GI tract.
Inventors: |
Shuros; Allan C.; (St. Paul,
MN) |
Correspondence
Address: |
SCHWEGMAN, LUNDBERG & WOESSNER/BSC-CRM
PO BOX 2938
MINNEAPOLIS
MN
55402
US
|
Family ID: |
38791294 |
Appl. No.: |
12/775223 |
Filed: |
May 6, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11422418 |
Jun 6, 2006 |
7734341 |
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12775223 |
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Current U.S.
Class: |
607/40 |
Current CPC
Class: |
A61N 1/36007
20130101 |
Class at
Publication: |
607/40 |
International
Class: |
A61N 1/36 20060101
A61N001/36 |
Claims
1. A system for delivering stimulation to a target region in a body
having lymphatic vessels and a gastrointestinal (GI) tract
including GI organs and nerves innervating the GI organs, the
target region including portions of the GI tract, the system
comprising: a first electrode assembly including a first electrode
base configured to be implanted into one of the lymphatic vessels
and a first stimulation electrode on the first electrode base, the
first electrode base configured to cause a portion of the one of
the lymphatic vessels to substantially alter its natural path to
contact the target region and maintain the contact between the
portion of the one of the lymphatic vessels and the target region
after an implantation of the first electrode assembly; and an
implantable medical device including: a GI stimulation circuit
adapted to deliver GI stimuli through the first stimulation
electrode; and an implant control circuit coupled to the GI
stimulation circuit, the implant control circuit adapted to control
the delivery of the GI stimuli using a plurality of stimulation
parameters selected to stimulate one or more of the GI organs and
the nerves innervating the GI organs.
2. The system of claim 1, wherein the first electrode base
comprises an elongate electrode base including one or more biases
each configured to cause the portion of the one of the lymphatic
vessels to substantially alter its natural path to contact the
target region, the elongate electrode base having a stiffness
allowing for maintaining the contact between the portion of the one
of the lymphatic vessels and the target region after the
implantation of the first electrode assembly.
3. The system of claim 1, wherein the first electrode base
comprises an expandable electrode base configured to cause the
portion of the one of the lymphatic vessels to substantially alter
its natural path to contact the target region, after being
expanded.
4. The system of claim 3, wherein the expandable electrode base
comprises a stent, and the first electrode is incorporated into or
integrated with the stent.
5. The system of claim 1, wherein the implant control circuit is
programmed to include stimulation parameters selected to create a
sensation discouraging food consumption.
6. The system of claim 5, wherein the implant control circuit is
programmed to include stimulation parameters selected to create a
sensation of satiety.
7. The system of claim 1, wherein the implant control circuit is
programmed to include stimulation parameters selected to increase
motor activities in the GI tract.
8. The system of claim 1, further comprising a first implantable
lead having a first distal end, a first proximal end configured to
be connected to the implantable medical device, and a first
elongate lead body between the first distal end and the first
proximal end, and wherein the first electrode assembly is
incorporated into the first implantable lead.
9. The system of claim 8, wherein the first electrode assembly is
incorporated into the first distal end.
10. The system of claim 8, wherein the first electrode assembly is
incorporated into the first elongate lead body.
11. The system of claim 8, wherein the first electrode assembly
further comprises a second stimulation electrode on the first
electrode base, and the GI stimulation circuit is adapted to
deliver the GI stimuli through the first stimulation electrode and
the second stimulation electrode.
12. The system of claim 8, further comprising a second stimulation
electrode configured to be placed in a location external to the
lymphatic vessels, and wherein the GI stimulation circuit is
adapted to deliver the GI stimuli through the first stimulation
electrode and the second stimulation electrode.
13. The system of claim 12, further comprising a second implantable
lead configured to be subcutaneously implanted, the second
implantable lead having a second distal end including the second
stimulation electrode, a second proximal end configured to be
connected to the implantable medical device, and a second elongate
lead body between the distal end and the proximal end.
14. The system of claim 8, comprising a physiological sensor
adapted to sense a physiological signal, and wherein the
implantable medical device comprises a sensing circuit adapted to
receive and process the physiological signal, and the implant
control circuit is adapted to control the delivery of the GI
stimuli using the physiological signal.
15. The system of claim 14, wherein the implant control circuit
comprises a closed-loop controller adapted to provide feedback
control of the delivery of the GI stimuli using the physiological
signal.
16. The system if claim 14, wherein the physiological sensor is
adapted to sense a signal indicative of mechanical activities of
the GI tract, the sensing circuit is adapted to receive and process
the signal indicative of mechanical activities of the GI tract, and
the implant control circuit is adapted to control the delivery of
the GI stimuli using the signal indicative of mechanical activities
of the GI tract.
17. The system if claim 14, wherein the physiological sensor is
adapted to sense neural signals transmitting a sensation of
satiety, the sensing circuit is adapted to receive and process the
neural signals, and the implant control circuit is adapted to
control the delivery of the GI stimuli using the neural
signals.
18. The system of claim 1, comprising biopotential sensing
electrodes adapted to sense a biopotential signal, and wherein the
implantable medical device comprises a biopotential sensing circuit
coupled to the biopotential sensing electrodes and adapted to
process the biopotential signal, and the implant control circuit is
adapted to control the delivery of the GI stimuli using the
processed biopotential signal.
19. The system of claim 18, wherein the biopotential signal is
indicative of food intake, and the implant control circuit is
adapted to initiate the delivery of the GI stimuli when the
biopotential signal exceeds a predetermined threshold.
20. The system of claim 18, wherein the implant control circuit is
adapted to control the delivery of the GI stimuli to augment a
sensation of satiety when the biopotential signal indicates ongoing
food consumption and digestion.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 11/422,418, filed Jun. 6, 2006, which is hereby incorporated by
reference in its entirety.
[0002] This application is related to commonly assigned, U.S.
patent application Ser. No. 11/422,423, entitled "METHOD AND
APPARATUS FOR LYMPHATIC SYSTEM PACING AND SENSING," filed on Jun.
6, 2006, U.S. patent application Ser. No. 11/422,421, entitled
"METHOD AND APPARATUS FOR NEURAL STIMULATION VIA THE LYMPHATIC
SYSTEM," filed on Jun. 6, 2006, now abandoned, U.S. patent
application Ser. No. 11/422,417, entitled "METHOD AND DEVICE FOR
LYMPHATIC SYSTEM MONITORING," filed on Jun. 6, 2006, now issued as
U.S. Pat. No. 7,526,337, and U.S. patent application Ser. No.
11/422,414, entitled "METHOD AND DEVICE FOR ENDO-LYMPHATIC
STIMULATION," filed on Jun. 6, 2006, which are hereby incorporated
herein by reference in their entirety.
TECHNICAL FIELD
[0003] This document relates generally to medical devices and
particularly to an implantable system that delivers
gastrointestinal (GI) stimulation via one or more lymphatic
vessels.
BACKGROUND
[0004] Electrical stimulation has been applied to treat digestive
disorders and control body weight. Such electrical stimulation
includes delivering stimulation pulses to the organs or nerves of
the gastrointestinal (GI) tract, such as the stomach or vagus
nerves that regulate functions of the stomach. For example, to
treat morbid obesity associated with compulsive overeating,
electrical stimuli are delivered to the vagus nerves or the stomach
to create a sensation of satiety (fullness). The stimulation
results in loss of desire to eat in a patient with obesity
associated with overeating. When the patient's natural biofeedback
fails to properly regulate his or her eating behavior, the
electrical stimulation may provide an effective feedback control
that discourages consumption of food in excessive quantities.
[0005] Implantable medical systems have been used to deliver
electrical stimulation to treat obesity. A typical implantable
electrical stimulation system includes an implantable stimulator
that delivers electrical stimulation pulses through a plurality of
stimulation electrodes. Depending on the location of the target
structure to be stimulated, the stimulation electrodes may be
incorporated onto the implantable stimulator and/or connected to
the implantable stimulator using one or more implantable leads. The
procedure of device implantation involves a certain level of risk
associated with factors including the degree of invasiveness and
anatomical complexity of each desirable stimulation site. The
desirable stimulation site may not be in or near a location with an
anatomical structure allowing for easy implantation of the
implantable stimulator and/or the lead(s). Therefore, given a
desirable stimulation site for obesity control, there is a need to
minimize the invasiveness of implanting a system that delivers
stimuli to that stimulation site.
SUMMARY
[0006] An implantable gastrointestinal (GI) stimulation system
includes an implantable medical device coupled to at least one
stimulus delivery device configured to be placed in one or more
lymphatic vessels of a patient, such as the patient's thoracic duct
and/or vessels branching from the thoracic duct. In one embodiment,
to control obesity, GI stimuli are delivered from the stimulus
delivery device to organs and/or nerves of the GI tract to create a
sensation of satiety and/or to expedite food movement through the
GI tract.
[0007] In one embodiment, a GI system includes an electrode
assembly and an implantable medical device. The electrode assembly
includes an electrode base configured to be implanted into a
lymphatic vessel and a stimulation electrode on the electrode base.
The electrode base is configured to cause a portion of the
lymphatic vessel to substantially alter its natural path to contact
a target region to which GI stimuli are delivered and maintain the
contact between the portion of the lymphatic vessel and the target
region after the implantation of the electrode assembly. The
implantable medical device includes a GI stimulation circuit and an
implant control circuit. The GI stimulation circuit delivers the GI
stimuli through the stimulation electrode. The implant control
circuit controls the delivery of the GI stimuli using a plurality
of stimulation parameters selected to stimulate one or more of the
organs and/or nerves of the GI tract.
[0008] In one embodiment, a method for delivering GI stimulation is
provided. GI stimuli are delivered to one or more of the organs
and/or nerves of the GI tract from an implantable medical device
through at least one stimulation electrode placed in a lymphatic
vessel.
[0009] This Summary is an overview of some of the teachings of the
present application and not intended to be an exclusive or
exhaustive treatment of the present subject matter. Further details
about the present subject matter are found in the detailed
description and appended claims. Other aspects of the invention
will be apparent to persons skilled in the art upon reading and
understanding the following detailed description and viewing the
drawings that form a part thereof. The scope of the present
invention is defined by the appended claims and their legal
equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The drawings illustrate generally, by way of example,
various embodiments discussed in the present document. The drawings
are for illustrative purposes only and may not be to scale.
[0011] FIG. 1 is an illustration of an embodiment of a
gastrointestinal (GI) stimulation system for obesity control and
portions of an environment in which the GI stimulation system is
used.
[0012] FIG. 2 is an illustration of another embodiment of the GI
stimulation system and portions of the environment in which the GI
stimulation system is used.
[0013] FIG. 3 is a block diagram illustrating an embodiment of an
implantable medical device of the GI stimulation system.
[0014] FIG. 4 is a block diagram illustrating a specific embodiment
of the implantable medical device.
[0015] FIG. 5 is a block diagram illustrating another specific
embodiment of the implantable medical device.
[0016] FIG. 6 is a block diagram illustrating an embodiment of an
external system of the GI stimulation system.
[0017] FIG. 7 is a block diagram illustrating an embodiment of the
external system being a patient management system.
[0018] FIG. 8 is a flow chart illustrating a method for delivering
GI stimulation for obesity control via the lymphatic system.
[0019] FIG. 9 is an illustration of a lymphatic vessel and a target
region for GI stimulation.
[0020] FIG. 10 is an illustration of an embodiment of an electrode
assembly for placement in the lymphatic vessel to allow for the GI
stimulation.
[0021] FIG. 11 is an illustration of an embodiment of another
electrode assembly for placement in the lymphatic vessel to allow
for the GI stimulation.
[0022] FIG. 12 is an illustration of an embodiment of another
electrode assembly for placement in the lymphatic vessel to allow
for the GI stimulation.
[0023] FIG. 13 is an illustration of an embodiment of another
electrode assembly for placement in the lymphatic vessel to allow
for the GI stimulation.
DETAILED DESCRIPTION
[0024] In the following detailed description, reference is made to
the accompanying drawings which form a part hereof, and in which is
shown by way of illustration specific embodiments in which the
invention may be practiced. These embodiments are described in
sufficient detail to enable those skilled in the art to practice
the invention, and it is to be understood that the embodiments may
be combined, or that other embodiments may be utilized and that
structural, logical and electrical changes may be made without
departing from the spirit and scope of the present invention.
References to "an", "one", or "various" embodiments in this
disclosure are not necessarily to the same embodiment, and such
references contemplate more than one embodiment. The following
detailed description provides examples, and the scope of the
present invention is defined by the appended claims and their legal
equivalents.
[0025] This document discusses an implantable gastrointestinal (GI)
stimulation system. The implantable GI stimulation system includes
an implantable medical device and at least one stimulus delivery
device placed a lymphatic vessel, such as the thoracic duct, of a
patient. The implantable medical device delivers GI stimuli to one
or more organs and/or nerves of the GI tract (i.e., GI organs and
nerves innervating the GI organs) through the stimulus delivery
device placed in the lymphatic vessel. In one embodiment, the
implantable GI stimulation system includes a transluminal lead
configured for insertion into a portion of the lymphatic vessel to
allow one or more stimulation electrodes to be placed in the
lymphatic vessel. The implantable medical device includes a GI
stimulation circuit that generates electrical stimulation
pulses.
[0026] The electrical stimulation pulses are delivered to one or
more target regions adjacent to the lymphatic vessel through the
one or more stimulation electrodes placed in the thoracic duct.
While the thoracic duct is specifically discussed in this document
as an example of such a lymphatic vessel, the GI stimuli are
delivered through any one or more lymphatic vessels, including, but
not limited to, the thoracic duct, lymphatic vessels branching from
the thoracic duct, the right lymphatic duct, and lymphatic vessels
branching from the right lymphatic duct.
[0027] The implantable GI stimulation system allows for obesity
control by using electrical stimulation to adjust the patient's
eating behavior and/or digestive activities. In one embodiment, one
or more target regions and parameters are selected to create a
sensation of satiety in the patient. Examples of such target
regions include the vagus nerves and the sensory receptors in the
stomach. The sensation of satiety is transmitted to the brain
through afferent sensory fibers in the vagus nerves. In another
embodiment, one or more target regions and parameters are selected
to regulate the GI motor functions for a quicker movement of food
through the GI tract to reduce alimentary absorption. Examples of
such target regions include the enteric nerves of the GI tract,
which control GI motor and secretive functions, and the vagus
nerves, which regulate gastric motor and secretive functions. In
another embodiment, one or more target regions and parameters are
selected to create a sensation of satiety while expediting the
movement of food through the GI tract.
[0028] While electrical stimulation is specifically discussed in
this document as an example, various embodiments of the GI
stimulation include stimulation of the organs and/or nerves of the
GI tract using any form of energy. While electrical stimulation
pulses are specifically discussed as the GI stimuli, various
embodiments of the GI stimulation may use electrical or
non-electrical stimuli. In various embodiments, the stimulus
delivery device placed in the thoracic duct generates or receives
the GI stimuli, which are then delivered to one or more stimulation
sites via the thoracic duct. The GI stimuli are in one or more
forms of energy such as electrical, magnetic, electromagnetic,
and/or acoustic (including ultrasonic) energies.
[0029] While the GI stimulation for obesity control is specifically
discussed in this document, the present subject matter generally
provides method and apparatus for stimulation of one or more organs
and/or nerves of the GI tract via the thoracic duct. Various
embodiments of the GI stimulation are not limited to applications
in obesity control. For example, by selecting suitable stimulation
sites and parameters, the present subject matter provides GI
stimulation for treatment of gastroparesis by delivering stimuli to
one or more organs and/or nerves of the GI tract using one or more
stimulus delivery devices such as electrodes placed in the thoracic
duct. Gastroparesis is a digestive disorder in which the normal
gastrointestinal motor functions are impaired, resulting in
prolonged movement of food through the GI system and, consequently,
reduced food consumption in unhealthily low quantities.
[0030] FIG. 1 is an illustration of an embodiment of a GI
stimulation system 100 and portions of an environment in which
system 100 is used. System 100 includes an implantable medical
device 110, a lead 112, an external system 130, and a telemetry
link 125 providing for communication between implantable medical
device 110 and external system 130. In various embodiments, system
100 delivers GI stimuli, including electrical stimulation pulses,
to one or more organs and/or nerves of a GI tract 108. The nerves
of GI tract 108 include nerves in GI tract 108 and nerves connected
to GI tract 108 to regulate functions thereof.
[0031] In the embodiments specifically discussed below, system 100
delivers GI stimuli, which are electrical stimulation pulses,
through at least one electrode placed in a thoracic duct 105, which
is part of the lymphatic system of a patient's body 101. The
lymphatic system includes lymph tissue, nodes, and vessels.
Interstitial fluid is absorbed from tissue, filtered through lymph
nodes, and empties into lymphatic vessels. FIG. 1 illustrates
portions of thoracic duct 105, a subclavian vein 102, a left
external jugular vein 104, a left internal jugular vein 103, and a
superior vena cava 106. Thoracic duct 105 connects to the venous
system at the juncture of subclavian vein 102 and a left internal
jugular vein 103. The fluid (lymph) from the lower body flows up to
thoracic duct 105 and empties into subclavian vein 102 from
thoracic duct 105. Thoracic duct 105 is located in the posterior
mediastinal and abdominal area of body 101, adjacent to portions of
the GI organs and nerves innervating the GI organs. Electrical
stimulation of these organs and/or nerves is delivered by using one
or more stimulation electrodes placed within thoracic duct 105.
Thoracic duct 105 is used as a conduit for advancing the one or
more stimulation electrodes to one or more locations from which
electrical stimulation can be delivered to one or more target
regions in body 101. The one or more targets regions include one or
more of the organs and nerves of GI tract 108. In various
embodiments, the electrical stimulation is delivered to one or more
the GI organs, including the stomach and the intestines, and nerves
innervating GI tract 108, including the parasympathetic nerves, the
sympathetic nerves, and the enteric nerves. The approach to the
process of electrode placement for GI stimulation via thoracic duct
105 has the potential of reducing the invasiveness of implantation
procedure under many circumstances.
[0032] Implantable medical device 110 generates the GI stimuli and
delivers the GI stimuli through lead 112. In one embodiment,
implantable medical device 110 also senses signals indicative of
digestive activities, such as neural signals in the nerves of GI
tract 108, using lead 112. In various embodiments, implantable
medical device 110 is capable of sensing other physiological
signals and/or delivering therapies in addition to the GI
stimulation. Examples of such additional therapies include neural
stimulation therapy, cardiac pacing therapy,
cardioversion/defibrillation therapy, cardiac resynchronization
therapy (CRT), cardiac remodeling control therapy (RCT), drug
therapy, cell therapy, and gene therapy. In various embodiments,
implantable medical device 110 delivers the GI stimulation in
coordination with one or more such additional therapies. In one
embodiment, in addition to lead 112, system 100 includes one or
more endocardial and/or epicardial leads for delivering pacing
and/or defibrillation pulses to the heart. In one embodiment,
system 100 also delivers neural stimulation pulses to restore,
regulate, or inhibit non-digestive functions. The combination of
the GI stimulation with one or more other therapies is valuable
because obesity is known to be associated with a variety of
pathological conditions.
[0033] Lead 112 is an implantable electrical stimulation lead
including a proximal end 114, a distal end 116, and an elongate
lead body 118 between proximal end 114 and distal end 116. Proximal
end 114 is coupled to implantable medical device 110. Distal end
116 includes at least one stimulation electrode for delivering the
GI stimuli to a target region. In one embodiment, as illustrated in
FIG. 1, distal end 116 includes stimulation electrodes 120 and 122.
In various other embodiments, distal end 116 includes one
stimulation electrode or three or more stimulation electrodes. In
one embodiment, a reference electrode is incorporated onto
implantable medical device 110. In a specific embodiment,
implantable medical device 110 includes a hermetically sealed
conductive housing that functions as the reference electrode. GI
stimuli are delivered using (i) two stimulation electrodes in
distal end 116 (electrodes 120 or 122), or (ii) a stimulation
electrode (electrode 120 or 122) in distal end 116 and the
reference electrode on implantable medical device 110. In various
embodiments, one or more of the stimulation electrodes are also
used for sensing one or more signals indicative of sensory and/or
motor activities associated with GI tract 108. The distal portion
of elongate lead body 118 (a substantial portion of elongate lead
body 118 coupled to distal end 116) is configured for placement in
subclavian vein 102 and thoracic duct 105, such that distal end 116
is placed in thoracic duct 105. During the implantation of lead
112, distal end 116 is inserted into subclavian vein 102 through an
incision, advanced in subclavian vein 102 toward thoracic duct 105,
inserted into thoracic duct 105 from subclavian vein 102, and
advanced in thoracic duct 105 until a predetermined location in
thoracic duct 105 is reached. In one embodiment, the position of
distal end 116 is adjusted by delivering test GI stimuli and
detecting the anticipated physiological responses. In one
embodiment, lead 112 includes a fixation mechanism configured to
stabilize distal end 116 in the determined position in thoracic
duct 105. Implantable medical device 110 is connected to proximal
end 114 and is subcutaneously implanted. One example of method and
apparatus for accessing the lymphatic system is discussed in U.S.
patent application Ser. No. ______, entitled "METHOD AND APPARATUS
FOR LYMPHATIC SYSTEM PACING AND SENSING," filed on even data
herewith (Attorney Docket No. 279.A69US1), assigned to Cardiac
Pacemakers, Inc., which is incorporated herein by reference in its
entirety. Specific examples of electrode configurations and
placement are also discussed in detail below, with reference to
FIGS. 9-13.
[0034] In one embodiment, lead 112 is configured such that distal
end 116 can be further advanced into a lymphatic vessel branching
from thoracic duct 105, such as the gastric branch, so that the
stimulation electrode can be placed in close proximity of a
desirable target region. After the distal end 116 is inserted into
thoracic duct 105, it is advanced to the junction of thoracic duct
105 and the branching lymphatic vessel and inserted to the
branching lymphatic vessel. While the placement of at least one
stimulation electrode in the thoracic duct is specifically
discussed as an example of providing for access to a target region,
the present subject matter generally includes introducing one or
more stimulus delivery devices such as one or more stimulation
electrodes to a target region via a lymphatic vessel. In various
embodiments, GI stimuli are delivered through one or more
stimulation electrodes placed in the lymphatic vessel and/or one or
more stimulation electrodes placed in a structure that is
accessible through the lymphatic vessel, including another
lymphatic vessel branching from the lymphatic vessel.
[0035] In one embodiment, system 100 includes two or more leads
each including one or more stimulation electrodes arranged to be
placed in thoracic duct 105. In another embodiment, system 100
includes a lead with a plurality of electrodes arranged for
delivering independently controllable GI stimuli to two or more
target regions.
[0036] External system 130 communicates with implantable medical
device 110 and provides for access to implantable medical device
110 by a physician or other caregiver. In one embodiment, external
system 130 includes a programmer. In another embodiment, external
system 130 is a patient management system including an external
device communicating with implantable medical device 110 via
telemetry link 125, a remote device in a relatively distant
location, and a telecommunication network linking the external
device and the remote device. The patient management system allows
access to implantable medical device 110 from a remote location,
for purposes such as monitoring patient status and adjusting
therapies. In one embodiment, telemetry link 125 is an inductive
telemetry link. In another embodiment, telemetry link 125 is a
far-field radio-frequency (RF) telemetry link.
[0037] Telemetry link 125 provides for data transmission from
implantable medical device 110 to external system 130. This
includes, for example, transmitting real-time physiological data
acquired by implantable medical device 110, extracting
physiological data acquired by and stored in implantable medical
device 110, extracting patient history data such as occurrences of
predetermined types of pathological events and therapy deliveries
recorded in implantable medical device 110, and/or extracting data
indicating an operational status of implantable medical device 110
(e.g., battery status and lead impedance). Telemetry link 125 also
provides for data transmission from external system 130 to
implantable medical device 110. This includes, for example,
programming implantable medical device 110 to acquire physiological
data, programming implantable medical device 110 to perform at
least one self-diagnostic test (such as for a device operational
status), and/or programming implantable medical device 110 to
deliver one or more therapies and/or to adjust the delivery of one
or more therapies.
[0038] FIG. 2 is an illustration of an embodiment of a GI
stimulation system 200 and portions of the environment in which
system 200 is used. System 200 includes the components of GI
stimulation system 100 and an additional lead 232. That is, GI
stimulation system 200 includes implantable medical device 110,
leads 112 and 232, external system 130, and telemetry link 125.
[0039] Lead 232 is an implantable electrical stimulation lead
including a proximal end 234, a distal end 236, and an elongate
lead body 238 between proximal end 234 and distal end 236. Proximal
end 234 is coupled to implantable medical device 110. Distal end
236 includes at least one electrode. In one embodiment, as
illustrated in FIG. 2, lead 232 includes an electrode 240 at distal
end 236. In another embodiment, lead 232 includes a plurality of
stimulation electrodes. In one embodiment, lead 232 is configured
for subcutaneous placement, external to thoracic duct 105. In one
embodiment, electrode 240 is used as a reference electrode.
[0040] Lead 232 expands the range of target regions to which the GI
stimuli can be delivered from implantable medical device 110. The
GI stimuli are directed by the location in body 101 where electrode
240 is subcutaneously placed. In various embodiments, GI stimuli
are delivered through any pair of electrodes of system 200,
including (i) two stimulation electrodes in distal end 116
(electrodes 120 and 122), (ii) a stimulation electrode in distal
end 116 (electrode 120 or 122) and electrode 240 (as the reference
electrode), or (iii) a stimulation electrode in distal end 116
(electrode 120 or 122) and the reference electrode on implantable
medical device 110. In one embodiment, distal ends 116 and 236 are
positioned such as a target structure for the GI stimulation is
approximately between a stimulation electrode in distal end 116
(electrode 120 or 122) and a reference electrode (electrode 240 or
the reference electrode on implantable medical device 110). This
allows for stimulation of a target region not immediately adjacent
to thoracic duct 105.
[0041] FIG. 3 is a block diagram illustrating an embodiment of an
implantable medical device 310, which is a specific embodiment of
implantable medical device 110. Implantable medical device 310
includes a GI stimulation circuit 346 and an implant control
circuit 348. GI stimulation circuit 346 delivers GI stimuli to a
pair of stimulation electrodes 342 and 344, through which the GI
stimuli are delivered to a target region in one or more nerves
and/or organs of GI tract 108. At least one of stimulation
electrodes 342 and 344 is placed in thoracic duct 105. Implant
control circuit 348 controls the delivery of the GI stimuli from GI
stimulation circuit 346.
[0042] In one embodiment, stimulation electrodes 342 and 344 are
both in thoracic duct 105 and adjacent to the target region, such
as electrodes 120 and 122. In another embodiment, stimulation
electrode 342 is in thoracic duct 105 and adjacent to the target
region, such as electrode 120 or 122, and stimulation electrode 344
is external to thoracic duct 105, such as electrode 240 or a
reference electrode on implantable medical device 310. In one
embodiment, the target region is approximately between stimulation
electrodes 342 and 344.
[0043] Implant control circuit 348 controls the delivery of the GI
stimuli from GI stimulation circuit 346 using stimulation
parameters tailored to the target region and the desired response
specified by the user such as a physician or other caregiver. The
stimulation parameters are pre-programmed or user-programmed into
implant control circuit 348. In various embodiments, the target
region includes one or more regions of the GI tract that are
adjacent to the thoracic duct in the abdominal region, including
the nerves innervating the GI tract. Examples of the target region
include one or more of the sympathetic nerves, the parasympathetic
nerves (including the vagus nerves), and various locations in the
stomach and intestine where the enteric nerves and sensory
receptors can be activated. Examples of the desired response
include one or more of a sensation of satiety, other sensations
discouraging excessive food consumption, and/or an increased speed
of food movement in the GI tract. Examples of the other sensations
discouraging excessive food consumption include symptoms of
gastroparesis (but not its actual occurrence), such as nausea,
bloating, and premature or extended feeling of satiety.
[0044] For illustration purposes, FIG. 3 shows the pair of
stimulation electrodes 342 and 344. In various embodiments, GI
stimulation circuit 346 delivers the GI stimuli through one or more
pairs of stimulation electrodes selected from a plurality of
stimulation electrodes. In one embodiment, GI stimulation circuit
346 includes two or more stimulation output channels each
delivering GI stimuli through a pair of stimulation electrodes. In
another embodiment, an electrode array with a plurality of
stimulation electrodes is placed in the thoracic duct, and one or
more stimulation electrodes are selected for delivering GI stimuli
by testing the physiological effect of stimulation associated with
each stimulation electrode.
[0045] FIG. 4 is a block diagram illustrating an embodiment of an
implantable medical device 410, which is another specific
embodiment of implantable medical device 110. Implantable medical
device 410 includes GI stimulation circuit 346, a sensing circuit
452, an implant control circuit 448, and an implant telemetry
circuit 458. One or more physiological sensors 450 are housed
within implantable medical device 410, incorporated onto
implantable medical device 410, and/or connected to implantable
medical device 410 using a lead.
[0046] Physiological sensor(s) 450 sense one or more physiological
signals such as signals indicative of GI functions, satiety, and/or
patient's various conditions associated with food consumption.
Sensing circuit 452 processes the one or more physiological signals
and produces signals indicative a need to start, stop, or adjust
the GI stimulation. Examples of such physiological signals include
neural and muscular signals indicative of mechanical activities of
the GI tract, neural signals in afferent nerves transmitting the
sensation of satiety to the brain, and signals indicative of blood
glucose level, blood lipid level, blood pH value, and other
parameters of blood chemistry. In one embodiment, physiological
sensor(s) 450 include one or both of stimulation electrodes 342 and
344, which are utilized as sensing electrodes. In one embodiment,
physiological sensor(s) 450 senses one or more physiological
signals indicative the onset or existence of a pathological
condition during which the patient's food intake should be
discouraged, stopped, or regulated.
[0047] Implant control circuit 448 is a specific embodiment of
implant control circuit 348 and controls the delivery of the GI
stimuli from GI stimulation circuit 346 using a plurality of
stimulation parameters. Implant control circuit 448 includes a
parameter storage circuit 454 and a parameter receiver 456.
Parameter storage circuit 454 stores values of the plurality of
stimulation parameters. Examples of such stimulation parameters
include pulse amplitude, pulse width, and pulse frequency (or
inter-pulse interval). The values of the plurality of stimulation
parameters are adjustable. Parameter receiver 456 receives values
of the plurality of stimulation parameters and updates parameter
storage circuit 454 with the received values. In one embodiment,
implant control circuit 448 controls the delivery of the GI stimuli
from GI stimulation circuit 346 by using one or more physiological
signals sensed by physiological sensor(s) 450 to adjust the
stimulation parameters. In various embodiments, each sensed
physiological signal is used as one or more of a triggering signal
to start or stop the GI stimulation, a safety assurance signal to
start, stop, or adjust the intensity of the GI stimulation, and a
feedback signal to provide closed-loop GI stimulation.
[0048] Implant telemetry circuit 458 transmits and receives data
via telemetry link 125. In one embodiment, the values of the
plurality of stimulation parameters are externally programmable,
and the programmed values are received from external system 130
through telemetry link 125.
[0049] FIG. 5 is a block diagram illustrating an implantable
medical device 510, which is a specific embodiment of implantable
medical device 410. Implantable medical device 510 includes GI
stimulation circuit 346, a biopotential sensing circuit 552, an
implant control circuit 548, and implant telemetry circuit 458.
[0050] Biopotential sensing circuit 552 is a specific embodiment of
sensing circuit 452 and processes a biopotential signal sensed
using biopotential sensing electrodes 562 and 564, which represent
a specific embodiment of physiological sensor(s) 450. Examples of
the biopotential signal include neural signals indicative of
activities in the nerves connected to the GI tract and
electromyographic signals indicative of the motor activities in the
GI tract. In one embodiment, biopotential sensing circuit 552
processes a neural signal indicative of a patient's condition that
can be improved by regulation of food consumption and/or digestion.
In one embodiment, biopotential sensing circuit 552 processes two
or more biopotential signals sensed using additional biopotential
sensing electrodes. In one embodiment, the biopotential signal is
sensed from the same site to which the GI stimuli are delivered,
and stimulation electrodes 342 and 344 are used as biopotential
sensing electrodes 562 and 564. In other words, stimulation
electrodes 342 and 344 and biopotential sensing electrodes 562 and
564 are physically the same pair of electrodes. In another
embodiment, the biopotential signal is sensed from a site different
from the site to which the GI stimuli are delivered. At least one
of stimulation electrodes 342 and 344 is not used as any of
biopotential sensing electrodes 562 and 564.
[0051] Implant control circuit 548 is a specific embodiment of
implant control circuit controls 448 and includes a closed-loop
controller 560, parameter storage circuit 454, and parameter
receiver 456. Implant control circuit controls 548 controls the
delivery of the GI stimuli from GI stimulation circuit 346 using a
plurality of stimulation parameters and the sensed and processed
biopotential signal. Closed-loop controller 560 controls the
delivery of the GI stimuli using the sensed and processed
biopotential signal as an input for feedback control. In one
embodiment, implant control circuit controls 548 initiates the
delivery of the GI stimuli when a sensed biopotential signal
indicative of the patient's food intake exceeds a predetermined
threshold. In another embodiment, implant control circuit 548
controls the delivery of the GI stimuli to augment the sensation of
satiety when a biopotential signal indicates ongoing food
consumption. In another embodiment, implant control circuit 548
initiates the delivery of the GI stimuli to augment the motor
activities of the GI tract when a biopotential signal indicates
ongoing food consumption and digestion. In another embodiment,
implant control circuit 548 controls the delivery of the GI stimuli
based on one or more biopotential signals indicative of a condition
of the patient that can benefit from regulation of food consumption
or ingestion.
[0052] FIG. 6 is a block diagram illustrating an embodiment of an
external system 630, which is a specific embodiment of external
system 130. External system 630 includes an external telemetry
circuit 670, an external controller 672, and a user interface 674.
External telemetry circuit 670 transmits and receives data via
telemetry link 125. External controller 672 controls the operation
of external system 630. User interface 674 allows a user such as a
physician or other caregiver to communicate with implantable
medical device 110 through external system 630. User interface 674
includes a presentation device 676 and a user input device 678.
User input device 678 allows for the programming of the values of
the plurality of stimulation parameters. In one embodiment,
presentation device 676 and user input device 678 are integrated or
partially integrated to include an interactive screen allowing for
programming of implantable medical device 110.
[0053] In one embodiment, external system 630 includes a
programmer. In another embodiment, external system 630 includes a
patient management system as discussed below with reference to FIG.
7.
[0054] FIG. 7 a block diagram illustrating an embodiment of an
external system 730, which is a specific embodiment of external
system 630. As illustrated in FIG. 7, external system 730 is a
patient management system including an external device 780, a
telecommunication network 782, and a remote device 784. External
device 780 is placed within the vicinity of implantable medical
device 110 and includes external telemetry system 670 to
communicate with the implantable medical device via telemetry link
125. Remote device 784 is in a remote location and communicates
with external device 780 through network 782. Remote device 784
includes user interface 674 to allow the physician or other
caregiver to monitor and treat a patient from a distant location
and/or allowing access to various treatment resources from the
remote location.
[0055] FIG. 8 is a flow chart illustrating a method for delivering
GI stimulation via thoracic duct. In one embodiment, the method is
performed using system 100 or system 200, including the various
embodiments of their components discussed above.
[0056] A GI stimulation lead is inserted into a lymphatic vessel of
a patient at 800. In one embodiment, this lymphatic vessel is the
thoracic duct. The GI stimulation lead is an implantable
transluminal lead having a proximal end configured for connection
to an implantable medical device and a distal end including one or
more stimulation electrodes. To insert the GI stimulation lead into
the thoracic duct such that GI stimuli can be delivered through the
stimulation electrode(s), an opening is made on the subclavian
vein, upstream from the junction of the subclavian vein and the
thoracic duct. The distal end of the GI stimulation lead is
inserted into the subclavian vein through the opening and advanced
toward the junction of the subclavian vein and the thoracic duct
downstream. Then, the GI stimulation lead is guided into the
thoracic duct and advanced in the thoracic duct until the distal
end reaches a target region to which the GI stimuli are delivered.
Examples of the target region include one or more of the nerves and
organs of the GI tract adjacent to the thoracic duct, such as
sympathetic nerves, parasympathetic nerves including the vagus
nerve, and portions of the stomach and intestines where the enteric
nerves and sensory receptors are distributed and excitable for
desired responses. In one embodiment, to further approach a
desirable target region, the distal end of the GI stimulation lead
is guided into a lymphatic vessel branching from the thoracic
duct.
[0057] The stimulation electrode(s) of the GI stimulation lead are
positioned in the lymphatic vessel, such as the thoracic duct or
the lymphatic vessel branching from the thoracic duct, at 810. In
one embodiment, after the distal end of the GI stimulation lead
reaches the region determined by the target region, test GI stimuli
are delivered. The distal end is moved in the thoracic duct and/or
the lymphatic vessel branching from the thoracic duct until it
reaches a position identified by detecting satisfactory responses
to the stimulation, such as evoked neural signals and/or other
anticipated physiological effects. The distal end with the
stimulation electrode(s) is then stabilized in that position.
[0058] One or more physiological signals are sensed at 820. In one
embodiment, at least one physiological signal is sensed to indicate
a need to start, stop, or adjust the delivery of the GI
stimulation. In another embodiment, at least one physiological
signal is sensed for monitoring, diagnostic, and/or therapeutic
purposes other then the GI stimulation. In one embodiment, one or
more neural and/or electromyographic signals are sensed. In a
specific embodiment, a neural or electromyographic signal is sensed
using the stimulation electrodes through which the GI stimuli are
delivered. In another embodiment, one or more signals each
indicative of a physiological function regulated by the GI
stimulation are sensed.
[0059] GI stimuli are delivered using the stimulation electrode(s)
positioned in the lymphatic vessel, such as the thoracic duct or
the lymphatic vessel branching from the thoracic duct, at 830. In
one embodiment, the GI stimuli are delivered through two
stimulation electrodes positioned in the thoracic duct or the
lymphatic vessel branching from the thoracic duct. In another
embodiment, the GI stimuli are delivered using a stimulation
electrode positioned in the thoracic duct or the lymphatic vessel
branching from the thoracic duct and another stimulation electrode
positioned in a location in the body external the lymphatic
vessels. In a specific embodiment, the GI stimuli are delivered to
a target region approximately between a pair of stimulation
electrodes. The delivery of the GI stimuli is controlled using a
plurality of stimulation parameters. Examples of the stimulation
parameters include pulse amplitude, pulse width, and pulse
frequency (or inter-pulse interval). These stimulation parameters
are adjustable. In one embodiment, a user such as a physician or
other caregiver programs one or more values of the plurality of
stimulation parameters. In one embodiment, the delivery of the GI
stimuli is also controlled using the one or more physiological
signals. The stimulation parameters are selected such that the GI
stimulation creates a sensation of satiety, other sensations
discouraging overeating, and/or increased motor activities in the
GI tract.
[0060] FIGS. 9-13 illustrate, by way of example, various
embodiments of an electrode assembly for placement in the lymphatic
vessel to allow for the GI stimulation. The electrode assembly
includes one or more electrode bases. One or more stimulation
electrodes are incorporated onto and/or integrated with each of the
one or more electrode bases. In one embodiment, the one or more
electrode bases each are formed as portion of a lead such as lead
112. In one specific embodiment, an electrode base is formed at
distal end 116 of lead 112, and stimulation electrodes 120 and 122
are on that electrode base. In another specific embodiment, one or
more electrode bases are formed in elongate lead body 118 of lead
112. In another embodiment, electrode bases are formed at distal
end 116 and elongate lead body 118 of lead 112 to provide for
delivery of the GI stimuli to multiple target regions.
[0061] FIG. 9 is an illustration of a lymphatic vessel 905 and a
target region 907 in their natural state. Target region 907 is a
region in the one or more organs and/or nerves of GI tract 108 to
which the GI stimuli are delivered. As illustrated in FIG. 9,
lymphatic vessel 905 and target region 907 are not in direct
contact, or not constantly in direct contact, with each other in
their natural state. Electrode assemblies illustrated in FIGS.
10-13 each cause and maintain a substantially constant and direct
contact between lymphatic vessel 905 and target region 907 by
substantially altering the natural path of lymphatic vessel 905.
Such a substantially constant and direct contact allows for a
reliable delivery of GI stimuli from one or more electrodes in
lymphatic vessel 905 to target region 907. In various embodiments,
lymphatic vessel 905 represents one of the thoracic duct, a vessel
branching from the thoracic duct, or any lymphatic vessel suitable
for placement of the one or more electrodes for the GI
stimulation.
[0062] FIG. 10 is an illustration of an embodiment of an electrode
assembly including an electrode base 1021 configured to be
implanted in lymphatic vessel 905 and a stimulation electrode 1020
on electrode base 1021. Electrode base 1021 has an elongate shape
and includes a bias configured to cause a portion of lymphatic
vessel 905 to substantially alter its natural path to contact
target region 907. The bias also allows electrode 1020 to be in
contact with the inner wall of lymphatic vessel 905 for delivering
the GI stimuli to target region 907. Electrode base 1021 has a
stiffness allowing for stabilizing the position of stimulation
electrode 1020 in lymphatic vessel 905 and maintaining the contact
between the portion of lymphatic vessel 905 and target region 907
after implantation. In one embodiment, electrode base 1021 is in a
helical form. In one embodiment, electrode base 1021 includes an
elongate body having shape memory characteristics such that it
returns to its preformed shape after the implantation procedure
during which a stylet or guide wire may be used. The shape memory
characteristics are provided by using a shape memory polymer such
as polyether polyurethane or a shape memory metal. In one
embodiment, the electrode assembly is coupled to implantable
medical device 110 via a lead such as lead 112. In a specific
embodiment, electrode base 1021 is formed at distal end 116 of lead
112, with stimulation electrode 1020 being stimulation electrode
120. In other specific embodiments, two or more stimulation
electrodes are incorporated into electrode base 1021.
[0063] FIG. 11 is an illustration of an embodiment of another
electrode assembly including an electrode base 1121 configured to
be implanted in lymphatic vessel 905 and stimulation electrodes
1120 and 1122, both on electrode base 1121. Electrode base 1121 has
an elongate shape and includes a bias configured to cause a portion
of lymphatic vessel 905 to substantially alter its natural path to
contact target region 907. The bias also allows electrodes 1120 and
1122 to be in contact with the inner wall of lymphatic vessel 905
for delivering the GI stimuli to target region 907 using either or
both of electrodes 1120 and 1122. Electrode base 1121 has the
stiffness allowing for stabilizing the positions of stimulation
electrodes 1120 and 1122 in lymphatic vessel 905 and maintaining
the contact between the portion of lymphatic vessel 905 and target
region 907 after implantation. In one embodiment, electrode base
1121 is in a helical form. In one embodiment, electrode base 1121
includes an elongate body having shape memory characteristics such
that it returns to its preformed shape after the implantation
procedure during which a stylet or guide wire may be used. The
shape memory characteristics are provided by using a shape memory
polymer such as polyether polyurethane or a shape memory metal. In
one embodiment, the electrode assembly is coupled to implantable
medical device 110 via a lead such as lead 112. In a specific
embodiment, electrode base 1121 is formed at distal end 116 of lead
112, with stimulation electrodes 1120 and 1122 being stimulation
electrodes 120 and 122. In other specific embodiments, one
stimulation electrode, or three or more stimulation electrodes, are
incorporated into electrode base 1121.
[0064] FIG. 12 is an illustration of an embodiment of another
electrode assembly including an electrode base 1121 with
stimulation electrodes 1120 and 1122 and another electrode base
1221 with stimulation electrodes 1220 and 1222. Electrode bases
1121 and 1221 are both configured to be implanted in lymphatic
vessel 905. Electrode bases 1121 has the elongate shape and
includes the bias configured to cause a portion of lymphatic vessel
905 to substantially alter its natural path to contact target
region 907. The bias also allows electrodes 1120 and 1122 to be in
contact with the inner wall of lymphatic vessel 905 for delivering
GI stimuli to target region 907 using either or both of electrodes
1120 and 1122. Electrode bases 1221 has an elongate shape and
includes a bias configured to cause a portion of lymphatic vessel
905 to substantially alter its natural path to contact a target
region 1207. The bias also allows electrodes 1220 and 1222 to be in
contact with the inner wall of lymphatic vessel 905 for delivering
GI stimuli to target region 1207 using either or both of electrodes
1220 and 1222. Electrode bases 1121 and 1221 each have a stiffness
allowing for stabilizing the positions of the stimulation
electrodes in lymphatic vessel 905 and maintaining the contact
between the portion of lymphatic vessel 905 and target region 907
after implantation. In one embodiment, electrode bases 1121 and
1221 are each in a helical form. In one embodiment, electrode bases
1121 and 1221 each include an elongate body having shape memory
characteristics such that it returns to its preformed shape after
the implantation procedure during which a stylet or guide wire may
be used. The shape memory characteristics are provided by using a
shape memory polymer such as polyether polyurethane or a shape
memory metal. In one embodiment, the electrode assembly is coupled
to implantable medical device 110 via a lead such as lead 112. In a
specific embodiment, electrode base 1121 is formed at distal end
116 of lead 112, with stimulation electrodes 1120 and 1122 being
stimulation electrodes 120 and 122, and electrode base 1221 is
formed in elongate lead body 118 of lead 112. In other specific
embodiments, one stimulation electrode, or three or more
stimulation electrodes, are incorporated into each of electrode
bases 1121 and 1221.
[0065] FIG. 13 is an illustration of an embodiment of another
electrode assembly including an electrode base 1321 and a
stimulation electrode 1320. Electrode base 1321 is expandable.
After being expanded, electrode base 1321 causes a portion of
lymphatic vessel 905 to substantially expand to contact target
region 907. The expansion of electrode base 1321 also allows
electrode 1320 to be in stable contact with the inner wall of
lymphatic vessel 905 for delivering GI stimuli to target region
907. In one embodiment, electrode base 1321 includes a stent that
is expanded in the lymphatic vessel to maintain patency of the
vessel. In one embodiment, stimulation electrode 1320 is
incorporated into the stent. In another embodiment, the stent is
made of metal and functions as stimulation electrode 1320. In
another embodiment, stimulation electrode 1320 is integrated into
the stent to be a portion of its structure. The stent also
stabilize the position of stimulation electrode 1320 in lymphatic
vessel 905 and prevents obstruction of the lymphatic flow. In one
embodiment, the electrode assembly is coupled to implantable
medical device 110 via a lead such as lead 112. In a specific
embodiment, the stent is incorporated into distal end 116 of lead
112. In another embodiment, the stent is incorporated into elongate
lead body 118 of lead 112. In another embodiment, two or more
stents are incorporated into elongate lead body 118 and/or distal
end 116 of lead 112.
[0066] It is to be understood that the above detailed description
is intended to be illustrative, and not restrictive. Other
embodiments will be apparent to those of skill in the art upon
reading and understanding the above description. The scope of the
invention should, therefore, be determined with reference to the
appended claims, along with the full scope of equivalents to which
such claims are entitled.
* * * * *